All-season tires used year-round must be capable of handling various types of road conditions, such as dry, wet, and snowy. A tire comprising for example, four circumferential grooves, a center land portion region defined by two inner circumferential main grooves, and two intermediate land portion regions defined by an outer circumferential main groove and inner circumferential main groove is known in the art as a tire that is capable of handling various types of road conditions (Japanese Unexamined Patent Application Publication No. 2010-184616A). In the tire of Japanese Unexamined Patent Application Publication No. 2010-184616A, a lug groove is provided in the center land portion region, and projections (peaks) constituted by locally raised portions of the groove bottom that are higher than in the other parts of the groove are formed in the lug groove near the tire centerline.
In accordance with the tire of Japanese Unexamined Patent Application Publication No. 2010-184616A, it is possible to improve the block rigidity of the center land portion, thereby putatively allowing for improved steering stability during on-road driving. The tire also effectively discharges water, putatively allowing for the prevention of hydroplaning.
An all-season tire preferably exhibits wear resistance on dry road surfaces and steering stability on wet and snowy road surfaces. However, the tire disclosed in Japanese Unexamined Patent Application Publication No. 2010-184616A does not exhibit a sufficient balance between these various capabilities.